EIGRP vs OSPF: When to Use Each
EIGRP vs OSPF in 2026. The technical differences, the convergence story, vendor reality (EIGRP is still Cisco-only in practice), and the design implications for new vs existing networks.
EIGRP
Enhanced Interior Gateway Routing Protocol, Cisco's hybrid distance-vector IGP. Articles tagged EIGRP cover the DUAL algorithm, composite metric and K values, stub routing, adjacency requirements, and Cisco IOS XE configuration.
Latest posts — page 3
EIGRP Configuration on Cisco IOS XE: Classic and Named Mode
EIGRP configuration on Cisco IOS XE: classic mode, named mode, network statements, passive-interface default, summarization, HMAC-SHA-256 authentication, and the production template.
EIGRP Metric and K Values Explained
The EIGRP composite metric formula, the five K values and why never to change them, the 64-bit wide metric for modern interfaces, and how to verify metrics in show output.
EIGRP DUAL Algorithm Deep Dive: Feasible Successors and the Real FD/RD Math
Everyone memorises RD < FD; nobody shows the arithmetic on a real router. Here it is on captured show ip eigrp topology output: one prefix with a feasible successor (409600 < 640000), one without (537600 > 512000), and a live failover where the route never left Passive.